Heat stress can reduce intake and milk production in lactating dairy cattle. During periods of excessive heat, when environmental temperatures and humidity are high, cooling systems such as combinations of fans, sprinklers, curtains, and natural ventilation systems may be used to cool the ambient air environment and the dairy cattle within the environment or may be used to directly cool the dairy cattle through evaporation of liquid from the skin surface. However, water supplies for cooling the air or for cooling the dairy cattle may be unavailable, and when available, sprinkler systems may drift or may provide inadequate amounts of water for sufficient cooling. Fans may be incorrectly placed for cooling, may fail and require maintenance and the amount of fan cooling may be limited by electrical capacities.
In some cases, heat stressed dairy cattle may be provided more access to drinking water, may be moved to shaded sides of a barn throughout the day or may be penned in small groups or separately penned in order to reduce the effects of heat stress. However, undersized water supply lines may limit access to water, and availability of stalls may be limited, which may prevent the dairy cattle from being moved to shaded areas or to separate or small group pens.
Even with cooling systems, supplemental water, shade or modified pen arrangements, in humid conditions, dairy cattle performance may be negatively impacted and intake and milk production may not reach levels observed during cool, less humid conditions.